Hi monks Today when a try to run some of my work code on perl 5.20 (before that i used 5.18) i encountered a strange behavior that i can't understand. The Sample code is: 

#!/usr/bin/env perl 

use strict;
use warnings;

use List::Util qw{ first };

my %hash = (
    ASD => 1,
    ZXC => 2,
    QWE => 3,
    TYU => 4
);

my $val = "qwe";
if(my $res = first { lc $_ eq $val } keys %hash) {
    print "Found: $res\n";
} else {
    print "Not found\n";
};

[download]
On perl version prior 5.20 result will be "Found: QWE" (as i expected), but when i run this code on perl 5.20 and beyound, result will be "Found: qwe". What is that ? Bug? Or i missed something ?

In reply to Strange behavior with List::Util qw{first} on perl >= 5.20 by papioko

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